In known vehicle seats, access to the rear row of seats may be eased by moving the front vehicle seat forward. Typically, a user manually moves the front seat forward, and later backward. In other words, the user introduces the forces necessary to move the motor vehicle seat forward and backward. Specifically the user grasps the upper part of the seat back and pushes the seat back together with the entire motor vehicle seat into the forwardly moved position. Thereafter, the user pushes the entire motor vehicle seat backward from a forwardly moved position to a position of use (i.e., position of utilization) wherein the user may sit and drive the vehicle. For ease of use, it is preferable for the seat to readily move forward and backward with as little force as possible applied by the user. As necessary, a motor may partially assist the forward and/or backward movement of the vehicle seat. It will be understood that in general configurations the user typically tilts the seat back rearward in a manual fashion.
Known configurations for movable vehicle seats are described in DE 10 2004 061 139 A1. Further, known forwardly movable vehicle seats are described in DE 101 51 762 A1 and to U.S. Pat. No. 5,352,019.
Known forwardly movable motor vehicle seats are typically equipped with a memory unit. The memory unit stores a position of utilization and facilitates movement of the seat to a previously adopted position of utilization when the vehicle seat is moved backward from a forwardly moved position.
A vehicle seat frame is connected to an underbody of a motor vehicle. Suited means are provided for this purpose. The invention relates to motor vehicle seat frames that are equipped with a longitudinal adjustment device comprising two pairs of rails that are lockable through a locking unit, and to motor vehicle seat frames that move forward through hinge arms articulated between the seat pan and an underbody. The invention further relates to other constructions for a longitudinal adjustment device.
As disclosed in previously cited DE 101 51 762 A1, a forwardly movable vehicle seat may include a stopper device used in connection with a seat back hinge. In a first stop position, the stopper device retains the seat back in the normal position of utilization. In a second stop position, the stopper device retains the seat back in a forwardly pivoted position. Through a special transmission means as disclosed, the stopper device is restricted to a second stop position wherein the seat back is in a front or forward portion of travel, and not in a rear portion. The disclosure contained in DE 101 51 762 A1 is incorporated in the present application.
Known forwardly movable vehicle seats to include the vehicle seat disclosed in DE 10 2004 061 139 A1 have yet to overcome one particular problem associated therewith. When known vehicle seats are moved backward from a forwardly moved position, a certain actuation force is required. The actuation force is usually applied by the user to the seat back. Upon application, the actuation force translates to and acts against the stopper device. By doing so, the actuation force advances the stopper device into the stop position in a manner more forcefully than without said actuation force. The disclosed vehicle seat incorporates two parts for ensuring that the seat back is retained in the second or forward stop position, namely a blocking cam and a limit stop. During actuation to release the seat back from the forward position, the blocking cam and limit stop are pushed against each other, such that the lever arm formed by the seat back transmits the actuation force thereby increasing the contact force between the blocking cam and limit stop. As a result, it is much more difficult to release the stopper device (i.e., separating the blocking cam and limit stop) during backward movement. Accordingly, actuation and release of the stopper device during backward movement requires a considerable release force.